Prognostic implication of extra-pancreatic organ invasion in resectable pancreas ductal adenocarcinoma in the pancreas tail

Objectives: To assess the prognostic significance of extra-pancreatic organ invasion in patients with resectable pancreatic ductal adenocarcinoma (PDAC) in the pancreas tail. Materials & Methods: This retrospective study included patients with resectable PDAC in the pancreas tail who received upfront surgery between 2014 and 2020 at a tertiary institution. Preoperative pancreas protocol computed tomography (CT) scans evaluated tumor size, peripancreatic tumor infiltration, suspicious metastatic lymph nodes, and extra-pancreatic organ invasion. The influence of extra-pancreatic organ invasion, detected by CT or postoperative pathology, on pathologic resection margin status was evaluated using logistic regression. The impact on recurrence-free survival (RFS) was analyzed using multivariable Cox proportional hazard models (clinical-CT and clinical-pathologic). Results: The study included 158 patients (mean age, 65 years +/- 8.8 standard deviation; 93 men). Extra-pancreatic organ invasion identified by either CT (p = 0.92) or pathology (p = 0.99) was not associated with a positive resection margin. Neither CT (p = 0.42) nor pathological (p = 0.64) extra-pancreatic organ invasion independently correlated with RFS. Independent predictors for RFS included suspicious metastatic lymph node (hazard ratio [HR], 2.05; 95 % confidence interval [CI], 1.08-3.9; p = 0.03) on CT in the clinical-CT model, pathological T stage (HR, 2.97; 95 % confidence interval [CI], 1.39-6.35; p = 0.005 for T2 and HR, 3.78; 95 % CI, 1.64-8.76; p = 0.002 for T3) and adjuvant therapy (HR, 0.62; 95 % confidence interval [CI], 0.42-0.92; p = 0.02) in the clinical-pathologic model. Conclusion: Extra-pancreatic organ invasion does not independently influence pathologic resection margin status and RFS in patients with resectable PDAC in the pancreas tail after curative-intent resection; therefore, it should not be considered a high-risk factor.